Periodontal disease in pregnant patients with rheumatic valvular disease: clinical and microbiological study

Ávila, Walkiria Samuel; Timerman, Lilia; Romito, Giuseppe Alexandre; Marcelino, Sílvia Linard; Neves, Itamara Lúcia Itagiba; Zugaib, Marcelo; Grinberg, Max

doi:10.1590/S0066-782X2011005000034

Abstracts

BACKGROUND: The periodontal disease during pregnancy of women with rheumatic valve disease imply infective endocarditis risks and higher rate of preterm birth and low birth weight. OBJECTIVE: To study the periodontal disease rate of women with rheumatic valve disease during pregnancy. METHODS: We studied 140 pregnant women who included 70 patients with rheumatic valve disease and 70 healthy women. The periodontal examination included: 1) periodontal clinical exam regard the follow variables: a) probing depth; b) gingival margin; c) clinical attachment level; d) bleeding on probing; e) plaque index and f) gingival index; and 2) microbiological test was performed in samples serum and gingival crevicular fluid and considered positive controls to Porphyromonas gingivalis, Tannerella forsithia e Aggregobacter actinomycetemcomitans. RESULTS: Age and parity were similar between groups; as single or combined the mitral valve disease was prevalent among the rheumatic valve lesion in 45 (32.1%) e 20 (28.5%) cases, respectively. Among the periodontal variables gingival margin (p=0.01) and plaque index (p=0.04) were different between groups. The periodontal disease was identified in 20 (14,3%) pregnant women, seven (10%) of them were patients with valve rheumatic disease and the remain 13 (18,6%) were healthy women, its percentual was not different between groups (p=0,147). Microbiological analyses of oral samples showed higher percentual of P. gingivalis in healthy pregnant women (p=0.004). CONCLUSION: The clinical and microbiological study during pregnancy showed comparable incidence of periodontal disease between women with rheumatic valve disease and healthy women.

Periodontitis; gengivitis; heart valve diseases; rheumatic disease; pregnancy

FUNDAMENTO: A doença periodontal representa risco à gestante portadora de valvopatia reumática, seja para contrair endocardite infecciosa, seja por propiciar complicações obstétricas. OBJETIVO: Estudar a frequência da doença periodontal em portadoras de valvopatia reumática durante a gravidez. MÉTODOS: Foram estudadas 140 gestantes, comparáveis quanto a idade e o nível socioeconômico, divididas em: 70 portadoras de doença valvar reumática e 70 mulheres saudáveis. Todas se submeteram a: 1) avaliação clínica odontológica que incluiu a análise dos seguintes parâmetros: 1.1) profundidade à sondagem, 1.2) distância da linha esmalte-cemento à margem gengival, 1.3) nível clínico de inserção, 1.4) índice de sangramento, 1.5) índice de placa bacteriana, e, 1.6) comprometimento de furca; e, 2) exame microbiológico nas amostras de saliva e do cone que considerou o controle positivo para as cepas das bactérias Porphyromonas gingivalis, Tannerella forsithia e Aggregobacter actinomycetemcomitans. RESULTADOS: A lesão valvar mitral foi prevalente (65 casos = 92,8%) dentre as gestantes cardiopatas. A comparação entre os grupos mostrou não haver diferenças entre idade e a paridade, e embora tenham sido verificadas diferenças entre as medidas da distância da linha esmalte-cemento à margem gengival (p = 0,01) e o índice de placa (p=0,04), a frequência da doença periodontal identificada em 20 (14,3%) gestantes, não foi diferente entre os grupos (p = 0,147). O exame microbiológico mostrou uma proporção maior da bactéria P. gingivalis na saliva de gestantes saudáveis (p = 0,004). CONCLUSÃO: O estudo clínico e microbiológico periodontal durante a gravidez demonstrou igual frequência da doença periodontal em portadoras de valvopatia reumática quando comparada às mulheres saudáveis.

Periodontite; gengivite; doenças das valvas cardíacas; doença valvar reumática; gravidez

FUNDAMENTO: La enfermedad periodontal, caracterizada por el estado inflamatorio e infeccioso permanente de la cavidad oral, representa riesgo a la gestante portadora de valvopatía reumática, ya sea para contraer endocarditis infecciosa, el sea por propiciar complicaciones obstétricas, tales como aborto espontáneo y prematuridad. OBJETIVO:Estudiar la frecuencia de la enfermedad periodontal en portadoras de valvopatía reumática durante la gravidez. MÉTODOS: Fueron estudiadas 140 gestantes, divididas por edad y por nivel socioeconómico, en dos grupos: 70 portadoras de enfermedad valvar reumática y 70 mujeres sanas. Todas se sometieron a: 1) evaluación clínica odontológica que incluyó el análisis de los siguientes parámetros: 1.1) profundidad al sondaje, 1.2) distancia de la línea esmalte-cemento al margen gingival, 1.3) nivel clínico de inserción, 1.4) índice de sangrado, 1.5) índice de placa bacteriana, y, 1.6) compromiso de furca; y, 2) examen microbiológico en las muestras de saliva y del cono que consideró el control positivo para las cepas de las bacterias Porphyromonas gingivalis, Tannerella forsithia y Aggregobacter actinomycetemcomitans. RESULTADOS:La edad y la paridad no fueron diferentes entre los grupos; la lesión valvar mitral fue prevalente (65 casos = 92,8%), tanto en la forma aislada (45 casos) cuanto asociada a la lesión valvar aórtica (20 casos). El análisis comparativo mostró que las medidas de la distancia de la línea esmalte-cemento al margen gingival (p = 0,01) y el índice de placa (p = 0,04) fueron diferentes entre los grupos; y la frecuencia de la enfermedad periodontal identificada en 20 (14,3%) gestantes, de las cuales 7 eran reumáticas (10,0%) y 13 sanas (18,6%), no fue diferente entre los grupos (p = 0,147). El examen microbiológico mostró una proporción mayor de la bacteria P. gingivalis en la saliva de gestantes sanas (p = 0,004). CONCLUSIÓN:El estudio clínico y microbiológico periodontal durante la gravidez demostró igual frecuencia de enfermedad periodontal en portadoras de valvopatía reumática cuando fueron comparadas a las mujeres sanas.

Periodontitis; gengivitis; enfermedades de las valvas cardíacas; enfermedades reumáticas; gravidez

^IInstituto do Coração do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo - São Paulo, SP - Brasil

^IIInstituto Dante Pazzanese de Cardiologia - São Paulo, SP - Brasil

^IIIDisciplina de Periodontia do Departamento de Estomatologia da Faculdade de Odontologia da Universidade de São Paulo - São Paulo, SP - Brasil

^IVDepartamento de Obstetrícia e Ginecologia do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo - São Paulo, SP - Brasil

Mailing address

ABSTRACT

BACKGROUND: The periodontal disease during pregnancy of women with rheumatic valve disease imply infective endocarditis risks and higher rate of preterm birth and low birth weight.

OBJECTIVE: To study the periodontal disease rate of women with rheumatic valve disease during pregnancy.

METHODS: We studied 140 pregnant women who included 70 patients with rheumatic valve disease and 70 healthy women. The periodontal examination included: 1) periodontal clinical exam regard the follow variables: a) probing depth; b) gingival margin; c) clinical attachment level; d) bleeding on probing; e) plaque index and f) gingival index; and 2) microbiological test was performed in samples serum and gingival crevicular fluid and considered positive controls to Porphyromonas gingivalis, Tannerella forsithia e Aggregobacter actinomycetemcomitans.

RESULTS: Age and parity were similar between groups; as single or combined the mitral valve disease was prevalent among the rheumatic valve lesion in 45 (32.1%) e 20 (28.5%) cases, respectively. Among the periodontal variables gingival margin (p=0.01) and plaque index (p=0.04) were different between groups. The periodontal disease was identified in 20 (14,3%) pregnant women, seven (10%) of them were patients with valve rheumatic disease and the remain 13 (18,6%) were healthy women, its percentual was not different between groups (p=0,147). Microbiological analyses of oral samples showed higher percentual of P. gingivalis in healthy pregnant women (p=0.004).

CONCLUSION: The clinical and microbiological study during pregnancy showed comparable incidence of periodontal disease between women with rheumatic valve disease and healthy women.

Keywords: Periodontitis; gengivitis; heart valve diseases; rheumatic disease; pregnancy.

Introduction

Periodontal disease comprehends a broad spectrum of alterations in periodontal tissue, which has an inflammatory and/or infectious origin. These alterations can take place during pregnancy, when physiological alterations in the oral cavity, attributed to hormonal mechanisms that occur during pregnancy, result in what is called pregnancy gingivitis¹, characterized by inflammation of the gingiva, cement and periodontal ligament and that predisposes the pregnant woman to periodontitis.

The periodontitis that affects around 15.0% of the Brazilian population^2,3 is a more severe clinical situation, as it involves the alveolar bone and is also associated with microorganisms, in the majority of cases gram-negative anaerobic bacilli, especially the bacteria Porphyromonas gingivalis (P. gingivalis), Tannerella forsythia (T. forsythia) and Aggregatibacter actinomycetemcomitans (A. actinomycetemcomitans)⁴.

During pregnancy, the permanent inflammatory and infectious state of the oral cavity⁵ represents a potential risk, either by favoring the occurrence of infectious endocarditis or by causing obstetric complications, such as miscarriage and prematurity⁶.

In this sense, the objective of the present study was to study the frequency of periodontal disease in women with rheumatic valvular disease during pregnancy.

Methods

From January2005 to July 2008, a cross-sectional study was carried out, which selected 140 pregnant women aged 18 to 35 years, consecutively treated at the Brazilian Public Health System (SUS). The group of women with rheumatic valvular disease consisted of 70 pregnant women treated at the Cardiopathy and Pregnancy Outpatient Clinic of the Valvular Cardiopathy Unit of Instituto do Coração (InCor). The control group consisted of 70 healthy pregnant women followed at the Prenatal Outpatient Clinic of Centro de Saúde Geraldo de Paula Souza, from the School of Public Health of the University of São Paulo (USP).

When included in the study, the groups of healthy and rheumatic pregnant women were paired for age, socioeconomic and cultural level and gestational age. All patients followed a protocol that included periodic clinical evaluation and dental clinical assessment, aiming at the identification of periodontal disease and the microbiological study of the oral cavity. In the group of rheumatic pregnant women, among the medications used for the cardiological treatment, the intramuscular injections of G benzathine (1,200,000 IU every 21 days) were maintained, for secondary prophylaxis of the rheumatic disease. Women with other comorbidities, such as arterial hypertension, diabetes mellitus, infectious diseases or those that had received antibiotic therapy during the previous three months, were excluded from the study.

The anamnesis included questions on oral hygiene habits. The patients were submitted to periodontal clinical assessment, which used the dental mirror and a probe with millimeter markings to record the following parameters: a) probing pocket depth (PPD), that corresponds to the distance (mm) between the gingival margin and the depth of the gingival sulcus or periodontal pocket; b) distance of the enamel-cement junction to gingival margin (ECJ/GM); c) clinical attachment level (CAL), which is the arithmetic difference of the values of PPD and ECJ/GM; d) the bleeding index (BI) on the four sides of each assessed tooth; e) bacterial plaque index (BPI); and f) furcation involvement.

The diagnosis of periodontal disease was based on the criteria by Tonetti and Claffey⁷. The microbiological analysis of saliva and cone samples used DNA extraction and polymerase chain reaction (PCR) techniques. The positive controls were cultivated strains of the bacteria P. gingivalis, T. forsythia and A. actinomycetemcomitans, according to Ashimoto's technique⁸.

The statistical analysis of the results used absolute and relative frequencies of data, central trend measurements (means and medians) and the dispersion of values (minimum and maximum values and standard deviations). The association tests (Pearson's Chi-square and Fisher's exact test) were calculated to assess the association between the presence of periodontal disease and the qualitative variables. The assessment of the periodontal disease took into account the clinical parameters: PPD, CAL, ECJ/GM, BI and BPI. The Mann-Whitney nonparametric and Pearson's Chi-square tests were used to compare the rheumatic and the healthy pregnant women. The level of significance was set at 5.0% for the rejection of the null hypothesis.

The study was approved by the Committee of Ethics in Research of Hospital das Clínicas of the School of Medicine (CAPPesp - process # 199/05) and of InCor (process # 2557-04/177) of the University of São Paulo (USP) and by the Committee of Ethics in Research of Instituto Dante Pazzanese de Cardiologia. The patients were included in the protocol after signing the Free and Informed Consent Form, according to the norms established by Resolution # 196 of October 10,1996, of the National Council of Health.

Results

A total of 61 patients (43.6%) were primiparas and the mean maternal age was not different (p < 0.451) between the groups, being 27 ± 4.6 years in rheumatic patients and 27 ± 5.1 in the healthy ones. The analysis of the distribution of valvular lesion in the rheumatic group showed that 45 (32.1%) of them presented mitral valve lesion, 5 (3.6%) presented aortic valve lesion and 20 (28.5%) presented a combination of aortic and mitral valve lesion. Fifteen of the 70 rheumatic patients had been submitted to cardiac surgery for biological valve replacement.

Clinical-odontological assessment

The analysis of the information on the oral hygiene showed that flossing was more common (p = 0.02) in the group of rheumatic pregnant women (48 = 68.5%) when compared to the healthy women (32 = 45.7%), whereas rinsing the mouth with mouthwash was 2.3-fold more common among the healthy pregnant women. The odontological and microbiological assessments were carried out at similar gestational ages (p = 0.801), generally at the 27.8^th ± 6.6 week of gestation in the rheumatic group and at the 29.8^th ± 7.6 week in the healthy group.

The mean number of preserved teeth was 24.1 teeth in the rheumatic group vs 24.0 in the healthy group. Periodontal disease was identified in 20 (14.3%) pregnant women, being 7 (10%) rheumatic and 13 (18.6%) healthy ones, with no statistical difference (p = 0.147) when comparing the two groups. The analysis of the periodontal parameters shown in Table 1 demonstrated differences between the groups regarding ECJ/GM and PI (p = 0.04).

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Microbiological assessment

The comparative analysis between the groups showed that the proportion of P. gingivalis was significantly higher in the saliva of pregnant women, when compared to the rheumatic ones (p = 0.004), but there was no difference regarding the bacteria T. forsythia and A. actinomycetemcomitans, in both saliva and cone samples (Table 2). The analysis of the distribution of types of bacteria among the 20 pregnant women that presented periodontal disease showed that the proportion of P. gingivalis and A. actinomycetemcomitans was significantly higher in the saliva and cone samples, respectively (Table 3).

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Obstetric data

There were no maternal obstetric complications during gestation and delivery. The gestational age at delivery, calculated as weeks of gestation, ranged from 36 to 42 (mean = 38.54 ± 6.65) weeks in the rheumatic and between 32 and 42 (mean = 39.28 ±7.65) weeks in the healthy pregnant women. Newborn weight ranged between 3,017 and 4,488 g (mean = 3,069 g ± 455) in the rheumatic group and between 3,290 and 4,260 g (mean = 3,286 g ± 455) in the healthy group. The comparative analysis showed that the gestational age at delivery and newborn weight were lower in the rheumatic group, showing statistical significance (respectively, p = 0.0036 and p = 0.034).

Discussion

The present study provides original data on the effect of periodontal disease in two special situations: pregnancy and rheumatic valvular disease.

Hormonal alterations during gestation, changes in eating habits and poor oral hygiene habits are factors that favor the manifestation of gestational gingivitis, common during the pregnancy-puerperium cycle^9,10. That is further complicated by the lack of access to dental care and the myth about the safety of dental treatment, which predispose to periodontal disease during pregnancy¹¹.

Although the population considered in this study was exposed to all these factors, the incidence of 14.0% of periodontal disease was not different from the percentage found in the general population¹². Among the explanations for this finding are the sample's characteristics: young patients (mean of 27 years) who are known¹³ to present a lower risk of periodontal disease when compared to older patients and the exclusion of smokers and patients with diabetes mellitus, conditions known to elevate the risk for periodontal disease in the general population^14-15. It is noteworthy, however, that studies on the incidence of periodontal disease in cardiopathic patients with rheumatic valvular disease are scarce.

The present study showed that the proportion of 13 (18.6%) cases of periodontal disease in the healthy group and 7 (10.0%) cases in the rheumatic group did not present statistical difference. However, at the clinical examination, parameters such as distance of the enamel-cement junction (ECJ) to gingival margin (GM) and the bacterial plaque index (PI) were different in the healthy pregnant women.

Such findings might be explained by the better oral hygiene performed by the rheumatic pregnant women, who flossed more regularly than the healthy ones. Although they presented similar socioeconomic levels, the women with valvular disease are probably better informed on the potential cardiac risks associated with poor oral hygiene, the result of the continuing education received throughout the cardiological follow-up.

In this sense, it has been reinforced in daily practice that the chronic inflammatory and infectious state of the mouth contributes to intermittent bacteremia and the risk of infectious endocarditis in patients with valvular disease. In fact, Hull¹⁶ and Holmstrup¹⁷ demonstrated that the oral cavity is the main route of entry of etiological agents in infectious endocarditis.

Regarding the types of microbial agents in periodontal disease, the difficulties in recognizing their specificity are based on the large number of species, with 300 to 400 of them being found in bacterial biofilm¹⁸. Of this spectrum, possibly 10 to 20 species participate in the pathogenicity and periodontal destruction in periodontal disease¹⁹, with a prevalence of gram-negative anaerobic bacilli and among them, A. actinomycetemcomitans (Hacek group), P. gingivalis and P. intermedia, with a predominance in gingival samples²⁰.

The identification of a higher proportion of P. gingivalis in the saliva of healthy pregnant women in comparison with the rheumatic ones (54.3% vs 29.20%; p = 0.004) reinforces the explanation of a better oral health status of the cardiopathic patients, when compared to the healthy ones.

However, the positive influence of benzathine penicillin in the rheumatic group should be considered. Thus, the recommendation for maintaining the administration of this antibiotic every 21 days throughout pregnancy with the objective of preventing new rheumatic episodes might represent an additional benefit for the improvement of oral health and the prevention of periodontal disease during pregnancy.

In the present study, the prevalence of P. gingivalis in the saliva samples of patients that had periodontal disease corroborates the reports by Dietrich and Takeuchi¹⁹, who demonstrated that P. gingivalis was a very virulent pathogen and that its detection must be used as a clinical indicator for periodontal disease.

As for the obstetric evolution, our results did not allow us to correlate periodontal disease with the adverse effects in pregnancy. Although the literature has called attention to the association between periodontal disease with low birth weight and prematurity, due to the systemic inflammatory state, there is not enough evidence to allow the correlation of the effects of periodontal disease with com adverse obstetric outcomes²¹.

On the other hand, the significant proportion of low-weight newborns and the younger gestational age at birth verified in the group of rheumatic pregnant women are explained by the maternal cardiac output restrictions and beta-blocker use by the rheumatic pregnant women.

Regarding the maternal scenario, the absence of complications during the pregnancy-puerperium cycle is attributed to the non-inclusion of patients with arterial hypertension, diabetes mellitus and other morbidities, associated with the rigorous prenatal care provided by the multidisciplinary team.

Conclusion

The clinical-microbiological study of the oral cavity during pregnancy showed that the frequency of periodontal disease in women with rheumatic valvular disease was not different when compared to healthy pregnant women.

Acknowledgements

The research was supported by Fundação de Amparo à Pesquisa do Estado de São Paulo (process # 57931-2).

To the Prenatal Care Team of Centro de Saúde Geraldo de Paula Souza of the Public Health School of the University of São Paulo, for their support in referring the patients that constituted the sample, which included the healthy pregnant women.

Potential Conflict of Interest

No potential conflict of interest relevant to this article was reported.

Sources of Funding

This study was funded by FAPESP.

Study Association

This article is part of the thesis of doctoral submitted by Lilia Timerman, from Incor.

References

1. Raber-Durlacher JE, van Steengergen TJ, Van Der Velden U, de Graaff J, Abracham-Inpijn L. Experimental gingivitis during pregnancy and post-partum: clinical, endocrinological and microbiological aspects. J Clin Periodontal. 1994;21(8):549-58.
2. Abegg C. Oral hygiene habits among Brazilian adults in an urban area of southern Brazil. Rev Saúde Pública. 1997;31(6):586-93.
3. Gjermo P, Rosing CK, Susin C, Oppermann R. Periodontal diseases in Central and South America. Periodontol 2000;2002;29:70-8.
4. Sanz M, Lau L, Herrera D, Morillo JM, Silva A. Methods of detection of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis and Tannerella forsythensis in periodontal microbiology, with special emphasis on advanced molecular techniques: a review. J Clin Periodontol. 2004;31(12):1034-47.
5. Mombelli A. Periodontitis as an infectious disease: specific features and their implications. Oral Dis. 2003;9(Suppl. 1):6-10.
6. Agueda A, Ramon JM, Manau C, Guerrero A, Echeverria JJ. Periodontal disease as a risk factor for adverse pregnancy outcomes: a prospective cohort study. J Clin Periodontol. 2008;35(1):16-22.
7. Tonetti MS, Claffey N. Advances in the progression of periodontitis and proposal of definitions of a periodontitis case and disease progression for use in risk factor research. In: 5th European Workshop in Periodontology. J Clin Periodontol. 2005;32(Suppl. 6):210-3.
8. Ashimoto A, Chen C, Bakker I, Slots J. Polymerase chain reaction detection of 8 putative periodontal pathogens in subgingival plaque of gingivitis and advanced periodontitis lesions. Oral Microbiol Immunol. 1996;11(4):266-73.
9. Kinane DF PM, Peterson M, Stathopoulou PG. Environment and other modifying factors of the periodontal disease. J Periodontol. 2006;40:107-19.
10. Yalcin FEE, Soydinc M, Basegmez C, Issever H, Isik G, Berber L, et al. The effect of sociocultural status on periodontal conditions in pregnancy. J Periodontol. 2002;73(2):178-82.
11. Boggess, KA. Maternal oral healthy in pregnancy. Obstetric Gynecol. 2008;111(4):976-86.
12. Oliver RC, Brown LJ, Loe H. Periodontal diseases in the United States population. J Periodontol. 1998;69(2):269-78.
13. Dietrich T, Jimenez M, Krall Kaye EA, Vokonas PS, Garcia RI. Age-dependent associations between chronic periodontitis/edentulism and risk of coronary heart disease. Circulation. 2008;117(13):1668-74.
14. Haber J, Kent RL. Cigarette smoking in a periodontal practice. J Periodontol. 1992;63(2):100-6.
15. Kinane DF, Chestnutt IG. Relationship of diabetes to periodontitis. Curr Opin Periodontol. 1997;4:29-34.
16. Hull MW, Chow AW. An approach to oral infections and their management. Curr Infect Dis Rep. 2005;7(1):17-27.
17. Holmstrup P, Poulsen AH, Andersen L, Skuldbol T, Fiehn NE. Oral infections and systemic diseases. Dent Clin North Am. 2003;47(3):575-98.
18. Darveau RJP, Tanner A, Page RC. The microbial challenge in periodontitis. Periodontol 2000;1997;14:12-32.
19. Takeuchi Y, Umeda M, Sakamoto M, Benno Y, Huang Y, Ishikawa I. Treponema socranskii, Treponema denticola, and Porphyromonas gingivalis are associated with severity of periodontal tissue destruction. J Periodontol. 2001;72(10):1354-63.
20. Yano-Higuchi K, Takamatsu N, He T, Umeda M, Ishikawa I. Prevalence of Bacteroides forsythus, Porphyromonas gingivalis and Actinobacillus actinomycetemcomitans in subgingival microflora of Japanese patients with adult and rapidly progressive periodontitis. J Clin Periodontol. 2000;27(8):597-602.
21. Xiong X, Buekens P, Fraser WD, Beck J, Offenbacher J. Periodontal disease and adverse pregnancy outcomes: a systematic review. BJOG. 2006;113(2):135-43.

Periodontal disease in pregnant patients with rheumatic valvular disease - clinical and microbiological study

Walkiria Samuel Ávila^I; Lilia Timerman^II; Giuseppe Alexandre Romito^III; Sílvia Linard Marcelino^III; Itamara Lúcia Itagiba Neves^I; Marcelo Zugaib^IV; Max Grinberg^I

Publication Dates

Publication in this collection
01 Apr 2011
Date of issue
Apr 2011

History

Received
24 Feb 2010
Reviewed
26 July 2010
Accepted
28 July 2010

This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.

[1] 1. Raber-Durlacher JE, van Steengergen TJ, Van Der Velden U, de Graaff J, Abracham-Inpijn L. Experimental gingivitis during pregnancy and post-partum: clinical, endocrinological and microbiological aspects. J Clin Periodontal. 1994;21(8):549-58.

[2] 2. Abegg C. Oral hygiene habits among Brazilian adults in an urban area of southern Brazil. Rev Saúde Pública. 1997;31(6):586-93.

[3] 3. Gjermo P, Rosing CK, Susin C, Oppermann R. Periodontal diseases in Central and South America. Periodontol 2000;2002;29:70-8.

[4] 4. Sanz M, Lau L, Herrera D, Morillo JM, Silva A. Methods of detection of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis and Tannerella forsythensis in periodontal microbiology, with special emphasis on advanced molecular techniques: a review. J Clin Periodontol. 2004;31(12):1034-47.

[5] 5. Mombelli A. Periodontitis as an infectious disease: specific features and their implications. Oral Dis. 2003;9(Suppl. 1):6-10.

[6] 6. Agueda A, Ramon JM, Manau C, Guerrero A, Echeverria JJ. Periodontal disease as a risk factor for adverse pregnancy outcomes: a prospective cohort study. J Clin Periodontol. 2008;35(1):16-22.

[7] 7. Tonetti MS, Claffey N. Advances in the progression of periodontitis and proposal of definitions of a periodontitis case and disease progression for use in risk factor research. In: 5th European Workshop in Periodontology. J Clin Periodontol. 2005;32(Suppl. 6):210-3.

[8] 8. Ashimoto A, Chen C, Bakker I, Slots J. Polymerase chain reaction detection of 8 putative periodontal pathogens in subgingival plaque of gingivitis and advanced periodontitis lesions. Oral Microbiol Immunol. 1996;11(4):266-73.

[9] 9. Kinane DF PM, Peterson M, Stathopoulou PG. Environment and other modifying factors of the periodontal disease. J Periodontol. 2006;40:107-19.

[10] 10. Yalcin FEE, Soydinc M, Basegmez C, Issever H, Isik G, Berber L, et al. The effect of sociocultural status on periodontal conditions in pregnancy. J Periodontol. 2002;73(2):178-82.

[11] 11. Boggess, KA. Maternal oral healthy in pregnancy. Obstetric Gynecol. 2008;111(4):976-86.

[12] 12. Oliver RC, Brown LJ, Loe H. Periodontal diseases in the United States population. J Periodontol. 1998;69(2):269-78.

[13] 13. Dietrich T, Jimenez M, Krall Kaye EA, Vokonas PS, Garcia RI. Age-dependent associations between chronic periodontitis/edentulism and risk of coronary heart disease. Circulation. 2008;117(13):1668-74.

[14] 14. Haber J, Kent RL. Cigarette smoking in a periodontal practice. J Periodontol. 1992;63(2):100-6.

[15] 15. Kinane DF, Chestnutt IG. Relationship of diabetes to periodontitis. Curr Opin Periodontol. 1997;4:29-34.

[16] 16. Hull MW, Chow AW. An approach to oral infections and their management. Curr Infect Dis Rep. 2005;7(1):17-27.

[17] 17. Holmstrup P, Poulsen AH, Andersen L, Skuldbol T, Fiehn NE. Oral infections and systemic diseases. Dent Clin North Am. 2003;47(3):575-98.

[18] 18. Darveau RJP, Tanner A, Page RC. The microbial challenge in periodontitis. Periodontol 2000;1997;14:12-32.

[19] 19. Takeuchi Y, Umeda M, Sakamoto M, Benno Y, Huang Y, Ishikawa I. Treponema socranskii, Treponema denticola, and Porphyromonas gingivalis are associated with severity of periodontal tissue destruction. J Periodontol. 2001;72(10):1354-63.

[20] 20. Yano-Higuchi K, Takamatsu N, He T, Umeda M, Ishikawa I. Prevalence of Bacteroides forsythus, Porphyromonas gingivalis and Actinobacillus actinomycetemcomitans in subgingival microflora of Japanese patients with adult and rapidly progressive periodontitis. J Clin Periodontol. 2000;27(8):597-602.

[21] 21. Xiong X, Buekens P, Fraser WD, Beck J, Offenbacher J. Periodontal disease and adverse pregnancy outcomes: a systematic review. BJOG. 2006;113(2):135-43.